Semiconductor device and method of forming interposer frame electrically connected to embedded semiconductor die

ABSTRACT

A semiconductor device has an interposer frame mounted over a carrier. A semiconductor die has an active surface and bumps formed over the active surface. The semiconductor die can be mounted within a die opening of the interposer frame or over the interposer frame. Stacked semiconductor die can also be mounted within the die opening of the interposer frame or over the interposer frame. Bond wires or bumps are formed between the semiconductor die and interposer frame. An encapsulant is deposited over the interposer frame and semiconductor die. An interconnect structure is formed over the encapsulant and bumps of the first semiconductor die. An electronic component, such as a discrete passive device, semiconductor die, or stacked semiconductor die, is mounted over the semiconductor die and interposer frame. The electronic component has an I/O count less than an I/O count of the semiconductor die.

FIELD OF THE INVENTION

The present invention relates in general to semiconductor devices and,more particularly, to a semiconductor device and method of forming aninterposer frame electrically connected to an embedded semiconductor diewith bumps and bond wires.

BACKGROUND OF THE INVENTION

Semiconductor devices are commonly found in modern electronic products.Semiconductor devices vary in the number and density of electricalcomponents. Discrete semiconductor devices generally contain one type ofelectrical component, e.g., light emitting diode (LED), small signaltransistor, resistor, capacitor, inductor, and power metal oxidesemiconductor field effect transistor (MOSFET). Integrated semiconductordevices typically contain hundreds to millions of electrical components.Examples of integrated semiconductor devices include microcontrollers,microprocessors, charged-coupled devices (CCDs), solar cells, anddigital micro-mirror devices (DMDs).

Semiconductor devices perform a wide range of functions such as signalprocessing, high-speed calculations, transmitting and receivingelectromagnetic signals, controlling electronic devices, transformingsunlight to electricity, and creating visual projections for televisiondisplays. Semiconductor devices are found in the fields ofentertainment, communications, power conversion, networks, computers,and consumer products. Semiconductor devices are also found in militaryapplications, aviation, automotive, industrial controllers, and officeequipment.

Semiconductor devices exploit the electrical properties of semiconductormaterials. The atomic structure of semiconductor material allows itselectrical conductivity to be manipulated by the application of anelectric field or base current or through the process of doping. Dopingintroduces impurities into the semiconductor material to manipulate andcontrol the conductivity of the semiconductor device.

A semiconductor device contains active and passive electricalstructures. Active structures, including bipolar and field effecttransistors, control the flow of electrical current. By varying levelsof doping and application of an electric field or base current, thetransistor either promotes or restricts the flow of electrical current.Passive structures, including resistors, capacitors, and inductors,create a relationship between voltage and current necessary to perform avariety of electrical functions. The passive and active structures areelectrically connected to form circuits, which enable the semiconductordevice to perform high-speed calculations and other useful functions.

Semiconductor devices are generally manufactured using two complexmanufacturing processes, i.e., front-end manufacturing, and back-endmanufacturing, each involving potentially hundreds of steps. Front-endmanufacturing involves the formation of a plurality of die on thesurface of a semiconductor wafer. Each die is typically identical andcontains circuits formed by electrically connecting active and passivecomponents. Back-end manufacturing involves singulating individual diefrom the finished wafer and packaging the die to provide structuralsupport and environmental isolation.

One goal of semiconductor manufacturing is to produce smallersemiconductor devices. Smaller devices typically consume less power,have higher performance, and can be produced more efficiently. Inaddition, smaller semiconductor devices have a smaller footprint, whichis desirable for smaller end products. A smaller die size may beachieved by improvements in the front-end process resulting in die withsmaller, higher density active and passive components. Back-endprocesses may result in semiconductor device packages with a smallerfootprint by improvements in electrical interconnection and packagingmaterials.

In a conventional fan-out wafer level chip scale package (Fo-WLCSP), asemiconductor die is typically enclosed by an encapsulant. A top andbottom build-up interconnect structure are formed over opposite surfacesof the encapsulant. A redistribution layer (RDL) and insulating layerare commonly formed within the top and bottom build-up interconnectstructures. In addition, a conductive pillar is typically formed throughthe encapsulant for z-direction vertical electrical interconnect betweenthe top and bottom interconnect structures.

When stacking semiconductor devices, the interconnect requirements ofeach device must be considered. Some high-performance semiconductordevices, e.g. ASIC and DSP, require high input/output (I/O) count andhigh vertical interconnect capability, as well as adequate heatdissipation. Other semiconductor devices, such as memory, have fewerinterconnect requirements. The vertical interconnect arrangement forstacking dissimilar semiconductor devices calls for particular attentionof the specific interconnect requirements of each level.

SUMMARY OF THE INVENTION

A need exists for a vertical interconnect arrangement adapted forsemiconductor devices having dissimilar I/O requirements. Accordingly,in one embodiment, the present invention is a method of making asemiconductor device comprising the steps of providing a carrier,providing an interposer frame having a die opening in the interposerframe, mounting the interposer frame over the carrier, providing a firstsemiconductor die having an active surface and plurality of bumps formedover the active surface, mounting the first semiconductor die over thecarrier within the die opening in the interposer frame, forming aplurality of bond wires between the first semiconductor die andinterposer frame, depositing an encapsulant over the interposer frameand first semiconductor die, and forming an interconnect structure overthe encapsulant and bumps of the first semiconductor die.

In another embodiment, the present invention is a method of making asemiconductor device comprising the steps of providing a carrier,mounting an interposer frame over the carrier, mounting a firstsemiconductor die over the carrier disposed adjacent to the interposerframe, forming a first interconnect structure between the firstsemiconductor die and interposer frame, depositing an encapsulant overthe interposer frame and first semiconductor die, and forming a secondinterconnect structure over the encapsulant and first semiconductor die.

In another embodiment, the present invention is a method of making asemiconductor device comprising the steps of providing an interposerframe, mounting a first semiconductor die adjacent to the interposerframe, forming a first interconnect structure between the firstsemiconductor die and interposer frame, depositing an encapsulant overthe interposer frame and first semiconductor die, and forming a secondinterconnect structure over the encapsulant and first semiconductor die.

In another embodiment, the present invention is a semiconductor devicecomprising an interposer frame and first semiconductor die mountedadjacent to the interposer frame. A first interconnect structure isformed between the first semiconductor die and interposer frame. Anencapsulant is deposited over the interposer frame and firstsemiconductor die. A second interconnect structure is formed over theencapsulant and first semiconductor die.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a PCB with different types of packages mounted to itssurface;

FIGS. 2 a-2 c illustrate further detail of the representativesemiconductor packages mounted to the PCB;

FIGS. 3 a-3 c illustrate a semiconductor wafer with a plurality ofsemiconductor die separated by saw streets;

FIGS. 4 a-4 i illustrate a process of forming an interposer frame andembedded semiconductor die electrically connected with bumps and bondwires;

FIG. 5 illustrates the interposer frame and embedded semiconductor dieelectrically connected with bumps and bond wires;

FIG. 6 illustrates the semiconductor die mounted adjacent to theinterposer frame and electrically connected with bumps and bond wires;

FIG. 7 illustrates the interposer frame and embedded semiconductor dieelectrically connected with bumps and bond wires;

FIG. 8 illustrates the interposer frame and embedded semiconductor dieelectrically connected with bumps;

FIG. 9 illustrates the interposer frame and embedded stackedsemiconductor die electrically connected with bumps and bond wires;

FIG. 10 illustrates stacked semiconductor die mounted adjacent to theinterposer frame and electrically connected with bumps and bond wires;

FIG. 11 illustrates a leadframe interposer and embedded semiconductordie electrically connected with bumps and bond wires;

FIG. 12 illustrates the semiconductor die mounted to the leadframeinterposer and electrically connected with bumps and bond wires;

FIG. 13 illustrates options for 3D stacking of an electronic componentover the semiconductor die embedded within the interposer frame and PCB;and

FIG. 14 a-14 e illustrate various electronic components for stackingover the interposer frame and embedded semiconductor die.

DETAILED DESCRIPTION OF THE DRAWINGS

The present invention is described in one or more embodiments in thefollowing description with reference to the figures, in which likenumerals represent the same or similar elements. While the invention isdescribed in terms of the best mode for achieving the invention'sobjectives, it will be appreciated by those skilled in the art that itis intended to cover alternatives, modifications, and equivalents as maybe included within the spirit and scope of the invention as defined bythe appended claims and their equivalents as supported by the followingdisclosure and drawings.

Semiconductor devices are generally manufactured using two complexmanufacturing processes: front-end manufacturing and back-endmanufacturing. Front-end manufacturing involves the formation of aplurality of die on the surface of a semiconductor wafer. Each die onthe wafer contains active and passive electrical components, which areelectrically connected to form functional electrical circuits. Activeelectrical components, such as transistors and diodes, have the abilityto control the flow of electrical current. Passive electricalcomponents, such as capacitors, inductors, resistors, and transformers,create a relationship between voltage and current necessary to performelectrical circuit functions.

Passive and active components are formed over the surface of thesemiconductor wafer by a series of process steps including doping,deposition, photolithography, etching, and planarization. Dopingintroduces impurities into the semiconductor material by techniques suchas ion implantation or thermal diffusion. The doping process modifiesthe electrical conductivity of semiconductor material in active devices,transforming the semiconductor material into an insulator, conductor, ordynamically changing the semiconductor material conductivity in responseto an electric field or base current. Transistors contain regions ofvarying types and degrees of doping arranged as necessary to enable thetransistor to promote or restrict the flow of electrical current uponthe application of the electric field or base current.

Active and passive components are formed by layers of materials withdifferent electrical properties. The layers can be formed by a varietyof deposition techniques determined in part by the type of materialbeing deposited. For example, thin film deposition may involve chemicalvapor deposition (CVD), physical vapor deposition (PVD), electrolyticplating, and electroless plating processes. Each layer is generallypatterned to form portions of active components, passive components, orelectrical connections between components.

The layers can be patterned using photolithography, which involves thedeposition of light sensitive material, e.g., photoresist, over thelayer to be patterned. A pattern is transferred from a photomask to thephotoresist using light. The portion of the photoresist patternsubjected to light is removed using a solvent, exposing portions of theunderlying layer to be patterned. The remainder of the photoresist isremoved, leaving behind a patterned layer. Alternatively, some types ofmaterials are patterned by directly depositing the material into theareas or voids formed by a previous deposition/etch process usingtechniques such as electroless and electrolytic plating.

Depositing a thin film of material over an existing pattern canexaggerate the underlying pattern and create a non-uniformly flatsurface. A uniformly flat surface is required to produce smaller andmore densely packed active and passive components. Planarization can beused to remove material from the surface of the wafer and produce auniformly flat surface. Planarization involves polishing the surface ofthe wafer with a polishing pad. An abrasive material and corrosivechemical are added to the surface of the wafer during polishing. Thecombined mechanical action of the abrasive and corrosive action of thechemical removes any irregular topography, resulting in a uniformly flatsurface.

Back-end manufacturing refers to cutting or singulating the finishedwafer into the individual die and then packaging the die for structuralsupport and environmental isolation. To singulate the die, the wafer isscored and broken along non-functional regions of the wafer called sawstreets or scribes. The wafer is singulated using a laser cutting toolor saw blade. After singulation, the individual die are mounted to apackage substrate that includes pins or contact pads for interconnectionwith other system components. Contact pads formed over the semiconductordie are then connected to contact pads within the package. Theelectrical connections can be made with solder bumps, stud bumps,conductive paste, or wirebonds. An encapsulant or other molding materialis deposited over the package to provide physical support and electricalisolation. The finished package is then inserted into an electricalsystem and the functionality of the semiconductor device is madeavailable to the other system components.

FIG. 1 illustrates electronic device 50 having a chip carrier substrateor printed circuit board (PCB) 52 with a plurality of semiconductorpackages mounted on its surface. Electronic device 50 may have one typeof semiconductor package, or multiple types of semiconductor packages,depending on the application. The different types of semiconductorpackages are shown in FIG. 1 for purposes of illustration.

Electronic device 50 may be a stand-alone system that uses thesemiconductor packages to perform one or more electrical functions.Alternatively, electronic device 50 may be a subcomponent of a largersystem. For example, electronic device 50 may be part of a cellularphone, personal digital assistant (PDA), digital video camera (DVC), orother electronic communication device. Alternatively, electronic device50 can be a graphics card, network interface card, or other signalprocessing card that can be inserted into a computer. The semiconductorpackage can include microprocessors, memories, application specificintegrated circuits (ASIC), logic circuits, analog circuits, RFcircuits, discrete devices, or other semiconductor die or electricalcomponents. The miniaturization and the weight reduction are essentialfor these products to be accepted by the market. The distance betweensemiconductor devices must be decreased to achieve higher density.

In FIG. 1, PCB 52 provides a general substrate for structural supportand electrical interconnect of the semiconductor packages mounted on thePCB. Conductive signal traces 54 are formed over a surface or withinlayers of PCB 52 using evaporation, electrolytic plating, electrolessplating, screen printing, or other suitable metal deposition process.Signal traces 54 provide for electrical communication between each ofthe semiconductor packages, mounted components, and other externalsystem components. Traces 54 also provide power and ground connectionsto each of the semiconductor packages.

In some embodiments, a semiconductor device has two packaging levels.First level packaging is a technique for mechanically and electricallyattaching the semiconductor die to an intermediate carrier. Second levelpackaging involves mechanically and electrically attaching theintermediate carrier to the PCB. In other embodiments, a semiconductordevice may only have the first level packaging where the die ismechanically and electrically mounted directly to the PCB.

For the purpose of illustration, several types of first level packaging,including wire bond package 56 and flip chip 58, are shown on PCB 52.Additionally, several types of second level packaging, including ballgrid array (BGA) 60, bump chip carrier (BCC) 62, dual in-line package(DIP) 64, land grid array (LGA) 66, multi-chip module (MCM) 68, quadflat non-leaded package (QFN) 70, and quad flat package 72, are shownmounted on PCB 52. Depending upon the system requirements, anycombination of semiconductor packages, configured with any combinationof first and second level packaging styles, as well as other electroniccomponents, can be connected to PCB 52. In some embodiments, electronicdevice 50 includes a single attached semiconductor package, while otherembodiments call for multiple interconnected packages. By combining oneor more semiconductor packages over a single substrate, manufacturerscan incorporate pre-made components into electronic devices and systems.Because the semiconductor packages include sophisticated functionality,electronic devices can be manufactured using cheaper components and astreamlined manufacturing process. The resulting devices are less likelyto fail and less expensive to manufacture resulting in a lower cost forconsumers.

FIGS. 2 a-2 c show exemplary semiconductor packages. FIG. 2 aillustrates further detail of DIP 64 mounted on PCB 52. Semiconductordie 74 includes an active region containing analog or digital circuitsimplemented as active devices, passive devices, conductive layers, anddielectric layers formed within the die and are electricallyinterconnected according to the electrical design of the die. Forexample, the circuit may include one or more transistors, diodes,inductors, capacitors, resistors, and other circuit elements formedwithin the active region of semiconductor die 74. Contact pads 76 areone or more layers of conductive material, such as aluminum (Al), copper(Cu), tin (Sn), nickel (Ni), gold (Au), or silver (Ag), and areelectrically connected to the circuit elements formed withinsemiconductor die 74. During assembly of DIP 64, semiconductor die 74 ismounted to an intermediate carrier 78 using a gold-silicon eutecticlayer or adhesive material such as thermal epoxy or epoxy resin. Thepackage body includes an insulative packaging material such as polymeror ceramic. Conductor leads 80 and bond wires 82 provide electricalinterconnect between semiconductor die 74 and PCB 52. Encapsulant 84 isdeposited over the package for environmental protection by preventingmoisture and particles from entering the package and contaminating die74 or bond wires 82.

FIG. 2 b illustrates further detail of BCC 62 mounted on PCB 52.Semiconductor die 88 is mounted over carrier 90 using an underfill orepoxy-resin adhesive material 92. Bond wires 94 provide first levelpackaging interconnect between contact pads 96 and 98. Molding compoundor encapsulant 100 is deposited over semiconductor die 88 and bond wires94 to provide physical support and electrical isolation for the device.Contact pads 102 are formed over a surface of PCB 52 using a suitablemetal deposition process such as electrolytic plating or electrolessplating to prevent oxidation. Contact pads 102 are electricallyconnected to one or more conductive signal traces 54 in PCB 52. Bumps104 are formed between contact pads 98 of BCC 62 and contact pads 102 ofPCB 52.

In FIG. 2 c, semiconductor die 58 is mounted face down to intermediatecarrier 106 with a flip chip style first level packaging. Active region108 of semiconductor die 58 contains analog or digital circuitsimplemented as active devices, passive devices, conductive layers, anddielectric layers formed according to the electrical design of the die.For example, the circuit may include one or more transistors, diodes,inductors, capacitors, resistors, and other circuit elements withinactive region 108. Semiconductor die 58 is electrically and mechanicallyconnected to carrier 106 through bumps 110.

BGA 60 is electrically and mechanically connected to PCB 52 with a BGAstyle second level packaging using bumps 112. Semiconductor die 58 iselectrically connected to conductive signal traces 54 in PCB 52 throughbumps 110, signal lines 114, and bumps 112. A molding compound orencapsulant 116 is deposited over semiconductor die 58 and carrier 106to provide physical support and electrical isolation for the device. Theflip chip semiconductor device provides a short electrical conductionpath from the active devices on semiconductor die 58 to conductiontracks on PCB 52 in order to reduce signal propagation distance, lowercapacitance, and improve overall circuit performance. In anotherembodiment, the semiconductor die 58 can be mechanically andelectrically connected directly to PCB 52 using flip chip style firstlevel packaging without intermediate carrier 106.

FIG. 3 a shows a semiconductor wafer 120 with a base substrate material122, such as silicon, germanium, gallium arsenide, indium phosphide, orsilicon carbide, for structural support. A plurality of semiconductordie or components 124 is formed on wafer 120 separated by saw streets126 as described above.

FIG. 3 b shows a cross-sectional view of a portion of semiconductorwafer 120. Each semiconductor die 124 has a back surface 128 and activesurface 130 containing analog or digital circuits implemented as activedevices, passive devices, conductive layers, and dielectric layersformed within the die and electrically interconnected according to theelectrical design and function of the die. For example, the circuit mayinclude one or more transistors, diodes, and other circuit elementsformed within active surface 130 to implement analog circuits or digitalcircuits, such as digital signal processor (DSP), ASIC, memory, or othersignal processing circuit. Semiconductor die 124 may also containintegrated passive devices (IPDs), such as inductors, capacitors, andresistors, for RF signal processing. In one embodiment, semiconductordie 124 is a flipchip type semiconductor die.

An electrically conductive layer 132 is formed over active surface 130using PVD, CVD, electrolytic plating, electroless plating process, orother suitable metal deposition process. Conductive layer 132 can be oneor more layers of Al, Cu, Sn, Ni, Au, Ag, or other suitable electricallyconductive material. Conductive layer 132 operates as contact padselectrically connected to the circuits on active surface 130.

An electrically conductive bump material is deposited over contact pads132 using an evaporation, electrolytic plating, electroless plating,ball drop, or screen printing process. The bump material can be Al, Sn,Ni, Au, Ag, Pb, Bi, Cu, solder, and combinations thereof, with anoptional flux solution. For example, the bump material can be eutecticSn/Pb, high-lead solder, or lead-free solder. The bump material isbonded to contact pads 132 using a suitable attachment or bondingprocess. In one embodiment, the bump material is reflowed by heating thematerial above its melting point to form spherical balls or bumps 134.In some applications, bumps 134 are reflowed a second time to improveelectrical contact to contact pads 132. The bumps can also becompression bonded to contact pads 132. Bumps 134 represent one type ofinterconnect structure that can be formed over contact pads 132. Theinterconnect structure can also use stud bump, micro bump, conductivepillars, or other electrical interconnect. Bumps 134 are electricallyconnected through contact pads 132 to circuits contained in activesurface 130.

In FIG. 3 c, semiconductor wafer 120 is singulated through saw street126 using a saw blade or laser cutting tool 136 into individualsemiconductor die 124.

FIG. 4 a-4 i illustrate, in relation to FIGS. 1 and 2 a-2 c, a processof forming an interposer frame and embedded semiconductor dieelectrically connected with bumps and bond wires. In FIG. 4 a, asubstrate or carrier 140 contains temporary or sacrificial base materialsuch as silicon, polymer, beryllium oxide, or other suitable low-cost,rigid material for structural support. An interface layer ordouble-sided tape 142 is formed over carrier 140 as a temporary adhesivebonding film or etch-stop layer.

In FIG. 4 b, a semiconductor wafer or substrate 144 contains a basematerial, such as silicon, germanium, gallium arsenide, indiumphosphide, or silicon carbide, for structural support. As asemiconductor wafer, substrate 144 can contain embedded semiconductordie or passive devices. Substrate 144 can also be a multi-layerlaminate, ceramic, tape, or leadframe.

A plurality of vias is formed through substrate 144 using laserdrilling, mechanical drilling, or deep reactive ion etching (DRIE). Thevias are filled with Al, Cu, Sn, Ni, Au, Ag, titanium (Ti), tungsten(W), poly-silicon, or other suitable electrically conductive materialusing electrolytic plating, electroless plating process, or othersuitable metal deposition process to form z-direction verticalinterconnect conductive vias 146.

An insulating or passivation layer 148 is formed over a surface ofsubstrate 144 and conductive vias 146 using PVD, CVD, printing, spincoating, spray coating, sintering or thermal oxidation. The insulatinglayer 148 contains one or more layers of silicon dioxide (SiO2), siliconnitride (Si3N4), silicon oxynitride (SiON), tantalum pentoxide (Ta2O5),aluminum oxide (Al2O3), polyimide, benzocyclobutene (BCB),polybenzoxazoles (PBO), or other material having similar insulating andstructural properties. A portion of insulating layer 148 is removed byan etching process to expose substrate 144 and conductive vias 146.

An electrically conductive layer or RDL 150 is formed over the exposedsubstrate 144 and conductive vias 146 using a patterning and metaldeposition process such as printing, PVD, CVD, sputtering, electrolyticplating, and electroless plating. Conductive layer 150 can be one ormore layers of Al, Cu, Sn, Ni, Au, Ag, or other suitable electricallyconductive material. Conductive layer 150 is electrically connected toconductive vias 146.

An insulating or passivation layer 152 is formed over an opposingsurface of substrate 144 and conductive vias 146 using PVD, CVD,printing, spin coating, spray coating, sintering or thermal oxidation.The insulating layer 152 contains one or more layers of SiO2, Si3N4,SiON, Ta2O5, Al2O3, polyimide, BCB, PBO, or other material havingsimilar insulating and structural properties. A portion of insulatinglayer 152 is removed by an etching process to expose substrate 144 andconductive vias 146.

An electrically conductive layer or RDL 154 is formed over the exposedsubstrate 144 and conductive vias 146 using a patterning and metaldeposition process such as printing, PVD, CVD, sputtering, electrolyticplating, and electroless plating. Conductive layer 154 can be one ormore layers of Al, Cu, Sn, Ni, Au, Ag, or other suitable electricallyconductive material. Conductive layer 154 is electrically connected toconductive vias 146.

In another embodiment, conductive vias 146 are formed through substrate144 after forming conductive layers 150 and/or 154. Conductive layers150 and 154 can be formed prior to insulating layers 148 and 152.

Conductive layers 150 and 154 and conductive vias 146 constitute az-direction vertical interconnect structure through substrate 144. Thecombination of substrate 144, conductive vias 146, and conductive layers150 and 154 constitute pre-formed interposer frame 156. A plurality ofdie openings 158 is formed through interposer frame 156, each dieopening 158 having sufficient area to contain semiconductor die 124. Thepre-formed interposer frame 156 is positioned over carrier 140 andmounted to interface layer 142.

FIG. 4 c shows the pre-formed interposer frame 156 mounted to carrier140 and interface layer 142. Semiconductor die 124 from FIGS. 3 a-3 c ispositioned over and mounted to interface layer 122 using a pick andplace operation. Die openings 158 aid with alignment of semiconductordie 124. Semiconductor die 124 is embedded within die openings 158 ofinterposer frame 156 with back surface 128 oriented toward carrier 140and interface layer 142.

FIG. 4 d shows semiconductor die 124 mounted to carrier 140 within dieopenings 158 of interposer frame 156. FIG. 4 e shows a plan view ofsemiconductor die 124 mounted within die openings 158 of interposerframe 156. In another embodiment, semiconductor die 124 is first mountedto carrier 140 and interposer frame 156 is mounted to carrier 140 aftermounting the semiconductor die.

In FIG. 4 f, a plurality of bond wires 160 is formed between contact pad132 of semiconductor die 124 and conductive layer 150 of interposerframe 156. The number of bumps 134 and bond wires 160 is determined bythe electrical functionality and vertical interconnect requirements ofsemiconductor die 124.

An encapsulant or molding compound 162 is deposited over semiconductordie 124 and interposer frame 156 and in the gap between the die andinterposer frame using a paste printing, compressive molding, transfermolding, liquid encapsulant molding, vacuum lamination, spin coating, orother suitable applicator. In another embodiment, encapsulant 162 isformed using film assisted mold (FAM). Encapsulant 162 can be polymercomposite material, such as epoxy resin with filler, epoxy acrylate withfiller, or polymer with proper filler. Encapsulant 162 is non-conductiveand environmentally protects the semiconductor device from externalelements and contaminants.

In FIG. 4 g, a portion of encapsulant 162 is removed by an etching orgrinding process to expose bumps 134. Alternatively, encapsulant 162 isdeposited with the proper volume to leave bumps 134 exposed.

In FIG. 4 h, a build-up interconnect structure 164 is formed overencapsulant 162 and bumps 134. The build-up interconnect structure 164includes an electrically conductive layer or RDL 166 formed using apatterning and metal deposition process such as sputtering, electrolyticplating, and electroless plating. Conductive layer 166 can be one ormore layers of Al, Cu, Sn, Ni, Au, Ag, or other suitable electricallyconductive material. One portion of conductive layer 166 is electricallyconnected to bumps 134 of semiconductor die 124. Other portions ofconductive layer 166 can be electrically common or electrically isolateddepending on the design and function of semiconductor die 124.

An insulating or passivation layer 168 is formed around conductive layer166 for electrical isolation using PVD, CVD, printing, spin coating,spray coating, sintering or thermal oxidation. The insulating layer 168contains one or more layers of SiO2, Si3N4, SiON, Ta2O5, Al2O3, or othermaterial having similar insulating and structural properties. A portionof insulating layer 168 can be removed by an etching process to exposeconductive layer 166 for additional electrical interconnect. In oneembodiment, build-up interconnect structure 164 contains a Cu wiring andsolder mask layer, Cu wiring with prepreg or ajinomoto build-up film(ABF) and solder mask layer, and BCB or polyimide insulating layer.

In FIG. 4 i, an electrically conductive bump material is deposited overbuild-up interconnect structure 164 and electrically connected to theexposed portion of conductive layer 166 using an evaporation,electrolytic plating, electroless plating, ball drop, or screen printingprocess. The bump material can be Al, Sn, Ni, Au, Ag, Pb, Bi, Cu,solder, and combinations thereof, with an optional flux solution. Forexample, the bump material can be eutectic Sn/Pb, high-lead solder, orlead-free solder. The bump material is bonded to conductive layer 166using a suitable attachment or bonding process. In one embodiment, thebump material is reflowed by heating the material above its meltingpoint to form spherical balls or bumps 170. In some applications, bumps170 are reflowed a second time to improve electrical contact toconductive layer 166. An under bump metallization (UBM) can be formedunder bumps 170. The bumps can also be compression bonded to conductivelayer 166. Bumps 170 represent one type of interconnect structure thatcan be formed over conductive layer 166. The interconnect structure canalso use stud bump, micro bump, or other electrical interconnect.

Semiconductor die 124 are singulated through interposer frame 156,encapsulant 162, and build-up interconnect structure 164 with saw bladeor laser cutting tool 172 into individual Fo-WLCSP 174. Carrier 140 andinterface layer 142 are removed by chemical etching, mechanical peeling,chemical mechanical polish (CMP), mechanical grinding, thermal bake, UVlight, laser scanning, or wet stripping to expose interposer frame 156.

FIG. 5 shows Fo-WLCSP 174 after singulation. Semiconductor die 124 iselectrically connected through contact pads 132 and bumps 134 tobuild-up interconnect structure 164. Semiconductor die 124 is alsoelectrically connected through bond wires 160 to conductive layer 150 ofinterposer frame 156 for z-direction vertical electrical interconnect toother semiconductor devices. With semiconductor die 124 mounted withinthe die opening of interposer frame 156, back surface 128 is exposed forheat dissipation. The height of Fo-WLCSP 174 is reduced withsemiconductor die 124 mounted within the die opening of interposer frame156. Bumps 170 have a fine pitch for greater routing density.

FIG. 6 shows an embodiment of Fo-WLCSP 180, similar to FIG. 5, withsemiconductor die 124 mounted with its back surface 128 adjacent to asurface of interposer frame 182 using die attach adhesive 184. Theinterposer frame 182 is similar to interposer frame 156, i.e.,conductive via 186 formed through substrate 188 and insulating layers189 and 191 and conductive layers 190 and 192 formed over opposingsurfaces of substrate 188, but without die openings. Semiconductor die124 is electrically connected through contact pads 132 and bumps 134 tobuild-up interconnect structure 164. Semiconductor die 124 is alsoelectrically connected through bond wires 160 to conductive layer 192 ofinterposer frame 182 for z-direction vertical electrical interconnect toother semiconductor devices.

FIG. 7 shows an embodiment of Fo-WLCSP 194, similar to FIG. 5, withbumps 196 disposed between conductive layer 150 of interposer frame 156and conductive layer 166 of build-up interconnect structure 164. Bumps196 provide additional z-direction vertical interconnect betweeninterposer frame 156 and build-up interconnect structure 164.

FIG. 8 shows an embodiment of Fo-WLCSP 198, similar to FIG. 5, butwithout bond wires between semiconductor die 124 and interposer frame156. Bumps 200 are disposed between conductive layer 150 of interposerframe 156 and conductive layer 166 of build-up interconnect structure164. Semiconductor die 124 is electrically connected through bumps 134,build-up interconnect structure 162, and bumps 200 to interposer frame156.

FIG. 9 shows an embodiment of Fo-WLCSP 202, similar to FIG. 5, withstacked semiconductor die. More specifically, semiconductor die 204 hasa back surface 205 and active surface 206 containing analog or digitalcircuits implemented as active devices, passive devices, conductivelayers, and dielectric layers formed within the die and electricallyinterconnected according to the electrical design and function of thedie. For example, the circuit may include one or more transistors,diodes, and other circuit elements formed within active surface 206 toimplement analog circuits or digital circuits, such as DSP, ASIC,memory, or other signal processing circuit. Semiconductor die 204 mayalso contain IPDs, such as inductors, capacitors, and resistors, for RFsignal processing. Contact pads 208 are formed over active surface 206and electrically connected to circuits within the active surface.Semiconductor die 204 is disposed within the die opening of interposerframe 156.

Semiconductor die 210 has a back surface 211 and active surface 212containing analog or digital circuits implemented as active devices,passive devices, conductive layers, and dielectric layers formed withinthe die and electrically interconnected according to the electricaldesign and function of the die. For example, the circuit may include oneor more transistors, diodes, and other circuit elements formed withinactive surface 212 to implement analog circuits or digital circuits,such as DSP, ASIC, memory, or other signal processing circuit.Semiconductor die 210 may also contain IPDs, such as inductors,capacitors, and resistors, for RF signal processing. Contact pads 214are formed over active surface 212 and electrically connected tocircuits within the active surface. Bumps 216 are formed over contactpads 214. Semiconductor die 210 is mounted with its back surface 211 toactive surface 206 of semiconductor die 204 with die attach adhesive218.

A plurality of bond wires 220 is formed between contact pad 208 ofsemiconductor die 204 and conductive layer 150 of interposer frame 156.A plurality of bond wires 222 is formed between contact pad 214 ofsemiconductor die 210 and conductive layer 150 of interposer frame 156,as well as contact pads 208 of semiconductor die 204. The number of bondwires 220 and 222 is determined by the electrical functionality andvertical interconnect requirements of semiconductor die 204 and 210.

Semiconductor die 204 is electrically connected through contact pads 208and bond wires 220 to interposer frame 156. Semiconductor die 210 iselectrically connected through contact pads 214 and bumps 216 tobuild-up interconnect structure 164. Semiconductor die 210 is alsoelectrically connected through bond wires 222 to contact pads 208 ofsemiconductor die 204 and to conductive layer 150 of interposer frame156 for z-direction vertical electrical interconnect to othersemiconductor devices.

FIG. 10 shows an embodiment of Fo-WLCSP 224, similar to FIG. 9, withsemiconductor die 204 mounted with its back surface 205 adjacent to asurface of interposer frame 226 using die attach adhesive 228. Theinterposer frame 226 is similar to interposer frame 182, i.e.,conductive vias 186 formed through substrate 188 and insulating layers189 and 191 and conductive layers 190 and 192 formed over opposingsurfaces of the substrate, but without die openings. Semiconductor die204 is electrically connected through contact pads 208 and bond wires220 to interposer frame 226. Semiconductor die 210 is electricallyconnected through contact pads 214 and bumps 216 to build-upinterconnect structure 164. Semiconductor die 210 is also electricallyconnected through bond wires 222 to contact pads 208 of semiconductordie 204 and to interposer frame 226 for z-direction vertical electricalinterconnect to other semiconductor devices.

FIG. 11 shows an embodiment of Fo-WLCSP 230 with leadframe interposer232. In one embodiment, leadframe interposer 232 is Cu. Semiconductordie 124 is disposed within a die opening of leadframe interposer 232.Semiconductor die 124 is electrically connected through contact pads 132and bumps 134 to build-up interconnect structure 164. Semiconductor die124 is also electrically connected through bond wires 234 to leadframeinterposer 232.

FIG. 12 shows an embodiment of Fo-WLCSP 236, with leadframe interposer238. In one embodiment, leadframe interposer 238 is Cu. Semiconductordie 124 is mounted with its back surface 128 to leadframe interposer 238with die attach adhesive 240. Semiconductor die 124 is electricallyconnected through contact pads 132 and bumps 134 to build-upinterconnect structure 164. Semiconductor die 124 is also electricallyconnected through bond wires 242 to leadframe interposer 238.

FIG. 13 shows an arrangement for 3D package stacking. Fo-WLCSP 174 fromFIG. 5 is mounted to substrate or PCB 250. Bumps 170 are electricallyconnected to contact pads 252 formed over PCB 250 for interconnectbetween semiconductor die 124 and PCB 250. The Fo-WLCSP embodiments ofFIGS. 6-12 can also be mounted to PCB 250.

An electronic component 254 is mounted to Fo-WLCSP 174. The electroniccomponent 254 can be implemented in various forms, e.g. land grid array(LGA), ball grid array (BGA), leaded semiconductor die, flipchipsemiconductor die, wafer level package, or discrete passive device. Forexample, electronic component 254 can be a flipchip type semiconductordie 256 with bumps 258 formed over contact pads 260 on active surface262, as shown in FIG. 14 a. The electronic component 254 can be adiscrete passive device 264, such as a capacitor, inductor, orcapacitor, as shown in FIG. 14 b.

In another embodiment, FIG. 14 c shows electronic component 254implemented as semiconductor die 270 with bumps 272 formed over contactpads 274 on active surface 276. Semiconductor die 272 is mounted tointerposer frame 278, which is similar to interposer frame 182. Discretepassive device 280, such as a capacitor, inductor, or capacitor, aremounted to interposer frame 278. Semiconductor die 270 and discretepassive devices 280 are electrically connected through interposer frames278 and 156 to semiconductor die 124 in Fo-WLCSP 174.

In another embodiment, FIG. 14 d shows electronic component 254implemented as stacked semiconductor die with a wire bond typesemiconductor die 282 mounted to leadframe interposer 284 with dieattach adhesive 286. A wire bond type semiconductor die 288 is mountedto semiconductor die 282 die attach adhesive 290. A plurality of bondwires 292 is formed between contact pads 294 on semiconductor die 282and leadframe interposer 284. A plurality of bond wires 296 is formedbetween contact pads 298 on semiconductor die 288 and leadframeinterposer 284. An encapsulant 300 is deposited over semiconductor die282 and 288, bond wires 292 and 296, and leadframe interposer 284.

In another embodiment, FIG. 14 e shows electronic component 254implemented as stacked semiconductor die including semiconductor die 302mounted to interposer frame 304 with die attach adhesive 306. Theinterposer frame 304 is similar to interposer frame 182. Semiconductordie 308 is mounted to semiconductor die 302 with die attach adhesive310. Semiconductor die 312 is mounted to semiconductor die 310 with dieattach adhesive 314. A plurality of bond wires 316 is formed betweencontact pads 318 on semiconductor die 302 and interposer frame 304. Aplurality of bond wires 320 is formed between contact pads 322 onsemiconductor die 308 and interposer frame 304. A plurality of bondwires 324 is formed between contact pads 326 on semiconductor die 312and interposer frame 304. An encapsulant 328 is deposited oversemiconductor die 302, 308, and 312, bond wires 316, 320, and 324, andleadframe interposer 304. A plurality of bumps 330 is formed overinterposer frame 304 opposite the stacked semiconductor die.

In 3D semiconductor device stacking, the lower semiconductor device istypically arranged for high speed, high functionality with correspondinghigh I/O count and interconnect requirements. For example, semiconductordie 124 could be an ASIC or DSP. The greater number of bumps 134 androuting options through build-up interconnect structure 164 provide therequisite level of interconnect needed for high performance devices. Theupper electronic component 254 is typically a memory device with lowerI/O count. For example, semiconductor die 282 and 288 could be memorydevices which are attached to Fo-WLCSP 174 containing the ASIC or DSPdevice. That is, semiconductor die 282 and 288 (memory devices)communicate with semiconductor die 124 (ASIC or DSP) through bond wires160, 292, and 296, interposer frame 156, and leadframe interposer 284.The vertical interconnect capability of bumps 134 and build-upinterconnect structure work well for DSP or ASIC type semiconductor die124, while bond wires 160 and interposer frame 156 and bond wires 160are suited for memory type semiconductor die 282 and 288.

While one or more embodiments of the present invention have beenillustrated in detail, the skilled artisan will appreciate thatmodifications and adaptations to those embodiments may be made withoutdeparting from the scope of the present invention as set forth in thefollowing claims.

1. A method of making a semiconductor device, comprising: providing acarrier; providing an interposer frame having a die opening in theinterposer frame; mounting the interposer frame over the carrier;providing a first semiconductor die having an active surface andplurality of bumps formed over the active surface; mounting the firstsemiconductor die over the carrier within the die opening in theinterposer frame; forming a plurality of bond wires between the firstsemiconductor die and interposer frame; depositing an encapsulant overthe interposer frame and first semiconductor die; and forming aninterconnect structure over the encapsulant and bumps of the firstsemiconductor die.
 2. The method of claim 1, wherein providing theinterposer frame includes: providing a substrate; forming a plurality ofconductive vias through the substrate; forming a first conductive layerover a first surface of the substrate, the first conductive layer beingelectrically connected to the conductive vias; and forming a secondconductive layer over a second surface of the substrate opposite thefirst surface, the second conductive layer being electrically connectedto the conductive vias.
 3. The method of claim 1, further includingmounting a second semiconductor die over the first semiconductor die andinterposer frame.
 4. The method of claim 1, wherein the secondsemiconductor die has an input/output count less than an input/outputcount of the first semiconductor die.
 5. The method of claim 1, furtherincluding forming a bump between interposer frame and interconnectstructure.
 6. The method of claim 1, further including mounting a secondsemiconductor die over the first semiconductor die prior to forming theinterconnect structure.
 7. A method of making a semiconductor device,comprising: providing a carrier; mounting an interposer frame over thecarrier; mounting a first semiconductor die over the carrier disposedadjacent to the interposer frame; forming a first interconnect structurebetween the first semiconductor die and interposer frame; depositing anencapsulant over the interposer frame and first semiconductor die; andforming a second interconnect structure over the encapsulant and firstsemiconductor die.
 8. The method of claim 7, further including mountingthe first semiconductor die over the carrier within a die opening in theinterposer frame.
 9. The method of claim 7, further including mountingthe first semiconductor die over the interposer frame.
 10. The method ofclaim 7, wherein the first interconnect structure includes bumps or bondwires.
 11. The method of claim 7, further including mounting a secondsemiconductor die over the first semiconductor die prior to forming thefirst and second interconnect structure.
 12. The method of claim 7,further including mounting an electronic component over the firstsemiconductor die and interposer frame.
 13. The method of claim 12,wherein the electronic component includes a discrete passive device,semiconductor die, or stacked semiconductor die.
 14. A method of makinga semiconductor device, comprising: providing an interposer frame;mounting a first semiconductor die adjacent to the interposer frame;forming a first interconnect structure between the first semiconductordie and interposer frame; depositing an encapsulant over the interposerframe and first semiconductor die; and forming a second interconnectstructure over the encapsulant and first semiconductor die.
 15. Themethod of claim 14, further including mounting the first semiconductordie within a die opening in the interposer frame.
 16. The method ofclaim 14, further including mounting the first semiconductor die overthe interposer frame.
 17. The method of claim 14, wherein the firstinterconnect structure includes bumps or bond wires.
 18. The method ofclaim 14, further including mounting an electronic component over thefirst semiconductor die and interposer frame.
 19. The method of claim18, wherein the electronic component includes a discrete passive device,semiconductor die, or stacked semiconductor die.
 20. The method of claim18, wherein the electronic component has an input/output count less thanan input/output count of the first semiconductor die.
 21. Asemiconductor device, comprising: an interposer frame; a firstsemiconductor die mounted adjacent to the interposer frame; a firstinterconnect structure formed between the first semiconductor die andinterposer frame; an encapsulant deposited over the interposer frame andfirst semiconductor die; and a second interconnect structure formed overthe encapsulant and first semiconductor die.
 22. The semiconductordevice of claim 21, wherein the first semiconductor die is mountedwithin a die opening in the interposer frame.
 23. The semiconductordevice of claim 21, wherein the first semiconductor die is mounted overthe interposer frame.
 24. The semiconductor device of claim 21, whereinthe first interconnect structure includes bumps or bond wires.
 25. Thesemiconductor device of claim 21, further including an electroniccomponent mounted over the first semiconductor die and interposer frame,wherein the electronic component includes a discrete passive device,semiconductor die, or stacked semiconductor die and the electroniccomponent has an input/output count less than an input/output count ofthe first semiconductor die.